The present invention pertains to deposition apparatuses and methods for forming layers over a semiconductor substrate.
Layer deposition techniques such as the various forms of chemical vapor deposition (CVD), pulsed CVD, and atomic layer deposition (ALD), are utilized to form layers upon surfaces, including surfaces of semiconductor substrates. These techniques involve providing precursor materials which react chemically to form a layer upon the surface.
Due to low reactivities of some precursor materials utilized in the deposition techniques described above, it is often desirable to enhance reactivity of precursors by generation of a metastable or an activated form of the precursor material. Once generated, the lifetimes of the metastable or activated species of the precursors are pressure dependent. Specifically, the lifetimes of metastable or activated species shorten as a result of increased pressure. Additionally, the number of unwanted side reactions between activated or metastable specie molecules increases with increased pressure. Generally, conventional layer deposition techniques that utilize metastable or activated precursors, generate or contain such precursors within a small volume under high pressure and thereby detrimentally affect the longevity of the metastable or activated form and promote unwanted side reactions.
Accordingly, it would be desirable to provide alternative methods and apparatuses for layer deposition.